DESCRIPTION The applicants propose to extend the evaluation of vitamin E and low-dose aspirin, as originally carried out in the Women's Health Study funded five years ago, in the primary prevention of cardiovascular disease and cancer in women. Four groups of women that have been randomized will continue to receive one of the following: (1) 100 mg aspirin on alternate days (2) 600 IU vitamin E on alternate days (3) both aspirin and vitamin E and (4) neither agent (placebo only). Approximately 39,900 women will be in the study, with more than 90 percent reporting taking pills. The trial will be conducted by mail based on methods developed for the Physicians' Health Study. Primary aims are to determine if aspirin or vitamin E reduces the risk of a combined cardiovascular endpoint consisting of nonfatal MI and stroke, as well as total cardiovascular mortality. The effect of these treatments on reduction of the risk of total cancers of epithelial cell origin will also be assessed. Secondary aims are broadened to determine if either of these treatments decreases the risk of individual endpoints of myocardial infarction, total stroke and total cardiovascular mortality, as well as individual endpoints of breast, lung, and colorectal cancer. Tertiary aims will determine if the combined treatments reduce risk of all important vascular events and total cancers of epithelial cell origin.